Timer



March 4, 1941. I 1 J. ARMSTRONG TIMER Filed July 23, 1936 INVENTOR ATTORNEY Patented Mar. 4, 1941 UNITED STATES FATENT FFICE TIMER Application July 23, 1936, Serial No. 92,128

11 Claims.

This invention relates to timers Vfor internal combustion engines, and aims to provide certain improvements therein. More particularly it relates to a timer of the type disclosed in my Patent No. 1,945,380, which provides positive means for bringing a set of movable contacts or breaker points into and out of contact with a set of stationary breaker points or contacts.

In the timer disclosed in my said patent there are shown two sets of oppositely-disposed stationary contacts and two sets of oppositely-disposed movable contacts, the movable contacts all being mounted on and movable with a rigid, rectangular, open frame, which is adapted to be reciprocated longitudinally and positively by an internally located cam, said internal cam being mounted on and adapted to rotate with the timer shaft, and imparting to the frame carrying the movable contacts a reciprocative motion which alternately makes and breaks contact between the respective sets of movable and stationary contacts.

It is well understood in the art that when contact is made between a pair of breaker points, current iiows through the primary coil, and that when the contact is broken, the changing flux surrounding the primary coil in turn induces a current in the secondary coil, which is used to produce a jump spark across the gap on the spark plugs. It is also well understood in the art that the contact between the breaker points should be maintained long 'enough to permit the primary coil to become saturated, so that the current may build up to its maximum before the contact is broken, thus inducing a stronger current in the secondary, and providing a better spark at the spark plugs. The period of time that a pair of breaker points are maintained in contact is referred to in the art as the amount of dwell of the timer. It is also understood the art that the amount of dwell required for a low speed engine is less than that required for a high speed or racing engine.

One of the objects of the present invention is to provide an improved timer which is designed to provide the desired amount of dwell.

Another object of the invention is to provide a timer in which the amount of dwell may be varied according to the speed at which the engine is designed to run.

Another object of the invention is to provide a timer in which the Contact between the breaker points is made positively, so as to eliminate bounce or rebound of the points when contact is made while the timer is running at high speed.

Another object of the invention is to provide a timer of the type referred to in which a sharp, exactly-timed break between the breaker points may be obtained.

A further object of the invention is to provide 5 a timer of the type disclosed in my said patent, having a resilient support for the rigid, rectangular frame which will permit of longitudinal reciprocation, but which will resist any tendency f scribed. 2h

Referring to the drawing which illustrates the preferred embodiment of the invention, and wherein similar reference numerals refer to similar parts in the several views- Figure 1 is a plan View of a timer constructed according to the present invention.

Fig. 2 is a View in front elevation of the timer shown in Fig. 1, the timer casing being shown in section.

Fig. 3 is a view in side elevation of the timer shown in Fig. 2, the timer casing being shown in section.

Fig. 4 is a fragmentary, plan View; and

Fig. 5 is a sectional view, in front elevation,

of Fig. 4, showing details of structure. 35

In the drawing it will be seen that a timer shaft 5 is journalled at its lower end in a bearing block 6, which is t into the lower end of a timer casing 1. At its upper end the timer casing is of enlarged diameter and cup-shaped, being adapted to receive a base plate 9 to which is attached all of the timer mechanism, the base plate being fastened to the casing by a pair of cap screws l0. As best seen in Fig. 5, the base plate is provided with a recess I'I into which may be fitted a ballbearing lfor the upper end of the timer shaft 5. Asthe precise structure of the ball bearing forms no part of the present invention, it is not here shown in order to avoid unnecessary complexity in the drawing. Any one of the standard forms of ball bearings may be used.

Fastened to the base plate 9 by screws I 1 is a pair of parallelly-disposed angle pieces I5, the vertical fianges of which act as supports for a pair of flat, blade-like resilient members I6 which are secured thereto, and which in turn serve as supports for a rectangular frame l1. The frame here shown is made of sheet metal and consists of a top portion I9, of which the center has been cut away, thus making it a substantially open top. At each end of the frame top is a downwardly turned flange I8 which is securely fastened to the resilient supporting members I6. The frame also has side members 20, and a bottom 2| which is out away similarly to the top portion I9. Each end member 22 of the frame is channel-shaped, as best seen in Fig. 5, and has fastened to it an auxiliary rigid channel member 23, which extends across the width of the frame and protrudes beyond the side edges thereof. The purpose of the auxiliary rigid channel members will presently be made apparent.

Within the open frame I1 and at opposite ends thereof are two fiber riding blocks 21, which provide bearing faces for a cam 28 which is mounted on the timer shaft 5 and adapted to rotate therewith, said cam being held in position on the shaft by a nut 3U. As will be seen from the drawing, the cam is located within the open frame IT, and is so designed as to be in constant contact with both riding blocks, and to impart to the frame a reciprocative motion as the shaft and cam rotate.

As mentioned above, the end members 22 of the frame are channel-shaped, and have secured to them auxiliary channel members 23, which extend across the width of the frame and out beyond the side edges thereof. Within these channel members 23 are leaf springs 35, which are riveted near their respective centers to the channel members and to the frame, said springs being pre-loaded or tensioned, and bearing at their unsecured ends against the webs of the channels 23. Each of said leaf springs 35 has Welded to it at each end thereof and on its inner face a breaker point 26, said breaker point being located on that portion of the leaf spring which extends beyond the side members of the frame. At points on the channel members 23 corresponding to the location of the breaker points on the leaf springs, holes have been drilled, said holes being large enough to freely accommodate the breaker points 26, which, as shown, protrude therethrough.

Mounted on each side of the frame and independently thereof, is a pair of supports I4, which are insulated from the base plate 9 and casing 1, and from each other, by suitable insulating material 41. Each of said supports is split, as shown in Fig. 3, and has at its upper end a threaded aperture into which is lscrewed the threaded end of breaker points 5|, said breaker points 5| having nuts 53 formed integrally therewith which facilitate manual adjustment of the breaker points by screwing them into or out of the supports 44, as may be desired. The supports 44, as previously mentioned, are split, and have cap screws 56 extending therethrough, which, when screwed up tightly, lock the threaded breaker points in position. The breaker points 5| are so mounted as to be brought into contact with the breaker points 26 when the frame |1 is caused to reciprocate by rotation of the cam 28. The four supports 44 are secured to the base plate by machine screws 6D, which are provided with ber ferrules 62 in order to insulate them from the base plate.

Extending downwardly from each of the four supports 44, is a binding post 63, which is screwed into the base of the support, being insulated from the base plate 9 by a fiber ferrule which fits around the shank of the binding post and which is held in position by an annular shoulder 66 formed thereon. The four binding posts also protrude through holes formed in the casing 1, said holes all being of sufficiently large diameter to prevent contact being made between the binding posts and the casing.

In operation, when the timer is used in an automobile gasoline engine, and when only one primary coil and one secondary coil are used, the four binding posts 63 will be connected to a common lead, which in turn will be connected to the primary coil (not shown). The other end of the primary coil will be connected to one terminal of a storage battery, and the other terminal of the battery customarily will be grounded to the automobile chassis. It will thus be apparent that when contact is made between breaker points 26 and 5|, as shown in Figs. 1 and 2, the circuit is complete and electric current flows through the primary coil, being grounded through the resilient supporting members I6 to the base plate and casing. When the contact between the breaker points is broken, this in turn induces a current in t'ne secondary which causes a jump spark across the spark plug gaps, in a manner well understood.

As previously mentioned, when the timer shaft 5 and cam 2B rotate, the cam imparts a longitudinal reciprocatory motion to the frame Il and moves the rigid channel members 23, their leaf springs 35 and Ibreaker points 26 in the direction of travel of the frame. This brings one pair of movable breaker points 25 (disposed on opposite sides of the frame) into contact with the adjacent pair of stationary breaker points 5|; While on the return stroke the other pair of movable breaker points make contact with the adjacent stationary breaker points. By the present invention, in order to provide the desired amount oi dwell, the movable breaker points 2S (Fig. l) make contact with the stationary breaker points 5| before the frame and its associated channel members 23 have completed their travel in one direction. As the frame continues to move in the same direction., the breaker points 2E ride backward against the tension of the spring 35 and through the apertures in the channel members 23. When the travel of the frame in one direction has been completed, and the travel in the other direction commenced, the tension on the leaf spring forces the movable breaker points back through the apertures in the channel member, until the leaf spring again bears against the web of the channel member. As previously mentioned, the leaf springs are pre-loaded. At the instant when the spring again bears against the web of the channel member, the contact between the breaker points is broken. In this Way a very definite, sharp, exactly-timed break is made, without danger of ybounce or rebound of the points. The same is true when the Contact bctween, the points is made.

It will be understood, of course, that the invention is not limited to the use of a reciprocating rectangular frame for moving the rigid members 23, their springs 35 and breaker points 2B, into and out of contact with the stationary breaker points 5|. It will be apparent that other means may be employed for moving these parts without departing from the spirit of the invention.

From the foregoing it will be apparent that the timer of the present invention insures sufficient dwell to permit of saturation of the primary coil.

If, however, it shouldbe 'desired to increase the amount of dwell, this may be done byscrewing the stationary breaker Ipoints outwardly from the supports, so that the contact with the movable breaker `points will be made earlier in the travel of the frame, which will maintain the points in contact longer. Conversely, it is possible to decrease the amount ofA dwell by screwing the stationary breaker points further into the supports 44. n

It will also be apparent that by mounting each of the stationary breaker points 5l in separate supports 44, which are insulated from the base plate 'and from each other, the present invention provides a timer onwhich one, two or four coils may be used. If one is used, the four binding posts 63 should be connected to a single lead, which in turn'is connected to the primary coil. If two coils are used, and theengine has single ignition, two end posts should be connected to one coil, and the other two posts connected to the second coil. If the engineis provided with `'dual ignition, the two binding posts on one side of the frame would be connected to one coil, and the two posts on the other side of the frame would -be connected to the other coil. In such a case, each set of points would work as -a separate unit. With four coils, each binding post would be connected to a separate'coil.

The advantage of being able to use two coils or four coils, aside from a dual ignition system wherein two are essential, is that you may give the points a greater dwell without interfering with the ehciency of the coil. In the timer herein disclosed, if one coil is used, for each complete revolution of the cam, contact will be made and broken six times. If therefore the dwell is increased beyond 60 of a revolution of the cani, the primary coil would always be in circuit. However, by using -two coils this situation is overcome. Another advantage of the use of two coils is to prevent the coils from becoming overheated.

In using the blade-like resilient vsupporting members Iii of a width substantially the same as the frame for supporting the frame I1, any tendency of the frame to twist or rotate due to friction on the riding blocks 21 or unequal pressures on the breaker points is eliminated. Also, there are no sliding or rotating parts which are apt to l wear and hence become loose and noisy.

While I have shown and described one embodiment of a timer constructed according to my present invention, it is obvious that various changes may be made therein without departing from the spirit of 'the invention; or from the scope of the appended claims.

What I claim is:

l. In a timer, `a substantially rigid frame, said frame having a pair of parallel, rigid end members, a pre-loaded leaf spring secured to and bearing against one of the faces of each of said end members, a breaker point mounted at each end of said springs and protruding through holes formed in said end members, means for reciprocating said frame longitudinally, and a set of stationary breaker points adapted to contact with said movable breaker points as the frame reciprocates.

2. In a timer, a casing, a substantially rigid, rectangular frame, means for reciprocating said frame longitudinally, a pair of at resilient supporting members secured to the end members of said frame and to said casing and permitting longitudinal reciprocation thereof, said supporting members being each disposed in a plane perpendicular to the plane oi movement of the frame, and a set of breaker Apoints mounted on said'frame and adapted to be brought into contact with another set of breaker points as the frame reci-procates.`

3. In a timer, a casing, a substantially rigid, rectangular frame, means for reciprocating said frame longitudinally, a pair of flat resilient supporting members secured to the end members of said frame and to said casing and permitting longitudinal reciprocation thereof, said supporting members being each disposed in a plane perpendicular to` the plane of movement of the frame and extending substantially the entire width of said frame, and `a set of breaker points mounted on said vframe and adapted to be brought into contact with another set of breaker points as the frame reciprocates.

4. In a timer, a rigid, rectangular frame, suitably supported, positive means for reciprocating said frame longitudinally, a set o breaker points mounted on said frame and movable therewith, a set of stationary breaker points mounted independently of said frame and adjacent said movable breaker points, said movable breaker points being adapted to contact said stationary breaker points upon reciprocation of the frame, and said stationary breaker points each being mounted in a separately formed support which is insulated from the timer casing and from the other supports.

5. In a timer, a substantially rigid frame, said frame having a pair of parallel, rigid end members, a lpre-loaded leaf spring secured to and bearing against one lof the faces of each of said end members, a breaker point mounted at each end of said springs and protruding through holes formed in said end members, means for reciprocating said frame longitudinally, and a set of stationary breaker points adapted to contact with said movable breaker points as the frame reciprocates, said movable breaker points being adapted to make contact with said stationary breaker points before the frame has completed its travel in one direction., and to ride backwardly against the tension ofthe leaf springs as the frame continues its travel, and to continue in contact until the spring again bears against the rigid `end members, at which time the contact is broken.

6. A timer comprising a movable rigid member serving as a breaker point support, a breaker point mounted thereon and movable therewith, a second breaker point mounted in a separate rigid support and in adjacent spaced relation with the first breaker point, a single positive means for moving said rigid member toward and away from said second breaker point to bring said points into and out of contact as the rigid member is so moved, and a pre-loaded spring mounting for one of said breaker points comprising a spring under tension at all times and bearing against and restrained by the adjacent rigid support when the points are out of contact, said spring being adapted to yield upon contact of the two points, whereby movement of the rigid mem- -ber may continue a definite distance after contact is made between the breaker points.

7. A timer comprising a movable rigid member, a pre-loaded spring carried by said rigid member, a movable breaker point under the tension of the pre-loaded spring at all times and capable of movement with and relatively to the rigid member, a stationary breaker point adjacent said movable breaker point, said preloaded spring lbearing against and restrained by said rigid member when the points are out of Contact and being adapted to yield upon contact of the points, and a single positive means for moving a pre-loaded spring carried by said rigid memf ber, a movable breaker point under the tension of the pre-loaded spring at all times and capable of movement with and relatively to the rigid member, a stationary breaker point adjacent said movable 'breaker point, said spring normally bearing against and restrained by said rigid member, and a single positive means for moving the rigid member toward and away from the stationary breaker point, whereby the movable breaker point may engage and make contact with the stationary breaker point while still permitting relative movementl of the rigid member.

9. A timer comprising a movable rigid member, a pre-loaded spring carried 'by said rigid member, a movable breaker point normally under the tension of the pre-loaded sprlng and protruding through a hole formed in said rigid member, said movable breaker point being capa-ble of movement with and relatively to the rigid member, a stationary breaker point adjacent said movable 4breaker point, and a single `positive means for moving said rigid member to bring said movablebreaker 'point into and out of contact with said stationary breaker point.

10. A timer comprising a movable rigid member, a pre-loaded leaf spring secured to said rigid member and having an unsecured `portion thereof `bearing against and restrained by said rigid member, a movable breaker point secured to said leaf spring at an unsecured portion thereof and adapted for movement With and relative to said rigid member, a stationary breaker point mounted adjacent said movable breaker point, and a single positive means for moving said rigid member to bring said movable breaker point into and out of contact with said stationary breaker point.

1l. A timer comprising a frame having a pair of laterally spaced parallel rigid members, a. support for said frame which permits simultaneous lateral displacement thereof, a pre-loaded leaf spring secured to each of said rigid members and having a free end thereof restrained by and bearing against said member, a movable breaker point mounted on the free end of said leaf springs, a stationary breaker point adjacent each movable ybreaker point and adapted to make contact therewith upon lateral displacement of the members, and a single ypositive means for moving said parallel rigid members laterally to bring the movable breaker points into and out of contact with said stationary breaker points.

LEONARD J. ARMSTRONG. 

